Microwave oven



FIG. 1 is a top, front and left-side perspective view of a microwave oven showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a left-side elevational view thereof;

FIG. 5 is a right-side elevational view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof. 

I claim the ornamental design for a microwave oven, as shown and described. 